The value of the fund and the change in that value is going to be related mostly to the contents of the fund. All the two versions are doing is basically allowing you to see a price both after and before exchange rates are taken into account.
If it's a US Index fund, investing in US stocks, then only a Canadian investor is likely to benefit or suffer from currency exchange rate changes. All a US investor would be doing is paying exchange rate fee's to their bank to change your money into CN$ Or the reverse if you live in Canada and buy the US version
For the Canadian investor this is effectively a 'international' fund of sorts, and currency risk is a part of that. As you will note that the fund has currently had a stronger return due to a weak Loonie, and that information is presented in BOTH versions of the fund, you could expect that for you, if the Loonie gets stronger, the performance (for you) of that fund to go down, no matter which version you invest in.
A Canadian investor who expects the Loonie to get stronger would be want to be investing in international instruments only to the extent they expected the return to outpace the changes in currency values, relative to what they could get returnwise in a domestic investment.